1. Field of the Invention
The present invention relates to a pole transformer load monitoring system using a wireless Internet network, and more particularly to a pole transformer load monitoring system using a wireless Internet network, which is capable of measuring a variety of loads (phase voltages, phase currents and temperatures) of a pole transformer placed on a distribution line in real time and transferring the results of the measurements to an operator in a branch operating station over the wireless Internet network so as to prevent losses resulting from overloaded and unbalanced states, thereby enhancing the quality of power supply and efficiently managing a distribution load.
2. Description of the Related Art
An example of conventional pole transformer load monitoring systems is shown in Korean Utility Model Publication No. 20-0174398 (published on Dec. 28, 1999).
FIG. 1 is a block diagram showing the construction of a pole transformer load monitoring system disclosed in the ""398 publication. As shown in this drawing, the pole transformer load monitoring system comprises an effective value converter 110 for converting current detected by a current transformer CT into an effective voltage, a battery 120 for charging and discharging itself with the current detected by the current transformer CT, a calculator 130 for amplifying the effective voltage from the effective value converter 110 and adjusting the gain of the amplified voltage, an analog/digital (A/D) converter 140 for converting an analog voltage from the calculator 130 into a BCD-coded digital signal, a data setting unit 150 for presetting a threshold value of overload current of a pole transformer, and a central processing unit (CPU) 160 operated according to a given program. In a normal state, the CPU 160 BCD-codes a peak load current value and continuously displays the coded value on a peak load current value display unit 170. The CPU 160 also continuously monitors whether a currently measured peak load current value of the pole transformer exceeds the overload current threshold value preset by the data setting unit 150. At the time that the currently measured peak load current value exceeds the preset overload current threshold value, the CPU 160 outputs an alarm control signal to an alarm unit 180 and an alarm transmission control signal to an alarm transmitter 190, respectively. The peak load current value display unit 170 acts to display the peak load current value coded by the CPU 160 on a liquid crystal display (LCD). When the currently measured peak load current value of the pole transformer exceeds the preset overload current threshold value, the alarm unit 180 flickers or lights up an alarm indication lamp and rings a buzzer, in response to the alarm control signal from the CPU 160. At this time, the alarm transmitter 190 transmits an overload alarm signal to a ground portable receiver in response to the alarm transmission control signal from the CPU 160.
However, the above-mentioned conventional pole transformer load monitoring system has a disadvantage in that it cannot monitor hystereses of loads, such as phase voltages and phase currents, in real time because it uses no wireless Internet network. This makes it impossible to efficiently manage the demand for electricity as well as to practically provide upgraded and advanced versions of electrical products.
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a pole transformer load monitoring system using a wireless Internet network, which is capable of monitoring phase voltages, phase currents, an internal temperature of a system body and an external temperature of a pole transformer in real time.
It is another object of the present invention to provide a pole transformer load monitoring system using a wireless Internet network, which is capable of providing current and voltage load factors by time zones.
It is a further object of the present invention to provide a pole transformer load monitoring system using a wireless Internet network, which is capable of outputting an alarm to a personal computer (PC) of a manager and a central control station at the time that a pole transformer is overloaded.
It is a further object of the present invention to provide a pole transformer load monitoring system using a wireless Internet network, which is capable of providing an indication of only an overloaded pole transformer.
It is another object of the present invention to provide a pole transformer load monitoring system using a wireless Internet network, which is capable of, when a pole transformer is overloaded, readily providing transformer information (light-loaded transformer information, overloaded transformer information, daily information, monthly information, quarterly information and yearly information).
It is yet another object of the present invention to provide a pole transformer load monitoring system using a wireless Internet network, which is capable of tracking an accurate fault point on a distribution line to shorten a recovery time.
In accordance with the present invention, the above and other objects can be accomplished by the provision of a pole transformer load monitoring system using a wireless Internet network, comprising phase current detection means for detecting current of each phase flowing through a secondary coil of a pole transformer; phase voltage detection means for detecting a voltage of each phase induced in the secondary coil of the pole transformer; internal temperature detection means for detecting an internal temperature of a system body; external temperature detection means for detecting an external temperature of the pole transformer; an analog/digital converter for converting the phase current detected by the phase current detection means, the phase voltage detected by the phase voltage detection means, the internal temperature detected by the internal temperature detection means and the external temperature detected by the external temperature detection means into digital signals; a microprocessor for performing an arithmetic operation for digital phase current, phase voltage, internal temperature and external temperature data from the analog/digital converter and controlling the entire operation of the system; a flash read only memory for sequentially storing phase current, phase voltage, internal temperature and external temperature values measured as a result of the arithmetic operation of the microprocessor; a watchdog for monitoring from periodic output signals from the microprocessor whether the microprocessor operates normally and outputting a reset signal to the microprocessor and flash read only memory upon determining that the microprocessor does not operate normally; a buffer for buffering an address signal from the microprocessor; a random access memory for storing output data from the microprocessor in its location corresponding to the address signal buffered by the buffer; a modem for receiving an output signal from the microprocessor, transmitting the received signal to a central control station via a base station and Internet network, receiving a control signal transmitted from the central control station and transferring the received control signal to the microprocessor; indication means for providing a visual indication of the transmission of the output signal from the microprocessor via the modem and a visual indication of the reception of the control signal from the central control station by the microprocessor; and an alternating current (AC)/direct current (DC) converter for converting an AC voltage applied between any one of three phases of the pole transformer and a neutral line into a DC voltage of a certain level and outputting the converted DC voltage as an operating voltage.